1. Field of the Invention
The present invention relates, in general, to a hinge apparatus for mobile phones and, more particularly, to a hinge apparatus for mobile phones, with a fixed cam installed in a rotary hinge part of the hinge apparatus, in place of a fixed hinge part of the apparatus, different from conventional hinge apparatuses, so that the design of elements of the hinge apparatus can be preferably changed so as to allow the elements to be easily and simply assembled into a single structure without being scratched, thus minimizing wobble of the hinge apparatus due to scratches of the elements and preventing a degradation in the operational performance of the hinge apparatus caused by the wobble.
2. Description of the Prior Art
As well known to those skilled in the art, conventional mobile phones are classified into flip-type phones with a hinged cover covering a variety of buttons of a main body, and folding-type phones with a folding main body. In accordance with the recent trend toward smallness and compactness of mobile phones, the folding-type phones have become more widely used than the flip-type phones.
FIG. 1 is a perspective view of a typical folding-type mobile phone. As shown in the drawing, the typical folding-type mobile phone is comprised of a main body 1 and a fold 2. The main body 1 has a microphone and a variety of buttons, and houses therein a variety of elements used for signal transmission and reception. A rechargeable battery used as a power source of the mobile phone is detachably mounted to the back of the main body 1.
The fold 2 is hinged to the main body 1 through a hinge apparatus so that the fold 2 is rotated around the hinge apparatus toward or away from the main body 1 to be closed or opened.
Such folding-type mobile phones are typically provided with a manual fold rotating mechanism designed to allow a user to manually open or close the fold relative to the main body. Nowadays, some models with a motor-operated fold rotating mechanism capable of automatically opening or closing the fold relative to the main body using a motor as well as allowing a user to manually open or close the fold as desired to enhance the convenience of users and functions of the phones have been proposed and used. Hinge apparatuses 10 for mobile phones with such motor-operated fold rotating mechanisms are so-called “manual/automatic hinge apparatuses”.
FIG. 2 is a sectional view of a conventional manual/automatic hinge apparatus installed in a folding-type mobile phone. As shown in the drawing, the conventional manual/automatic hinge apparatus 10 designed to allow a user to manually or automatically open or close a fold 2 relative to a main body 1 is comprised of a rotary hinge part 20 integrally provided at the fold 2, and two fixed hinge parts 30 and 31 integrally provided at the main body 1. The rotary hinge part 20 is hinged at both ends thereof to the two fixed hinge parts 30 and 31.
The rotary hinge part 20 of the hinge apparatus 10 has a motor-operated fold rotating mechanism which is set in a housing 21 and is used for automatically opening or closing the fold 2 relative to the main body 1 as desired. The motor-operated fold rotating mechanism is comprised of a power generating unit for generating a rotating drive force, a power transmission unit for selectively engaging with the power generating unit, and an elastic support member for applying an elastic biasing force to the power transmission unit to selectively engage or disengage the power transmission unit with or from the power generating unit in response to an external force applied to the fold by a user.
The power generating unit generates a rotating drive force to rotate the fold 2 relative to the main body 1 in either direction, and is comprised of a motor 22 for generating the rotating drive force, and a reduction gear assembly 23 for transmitting the rotating drive force of the motor 22 while lowering the rotating speed.
In a detailed description, the motor 22 is connected to a signal output unit (not shown) externally provided at a predetermined portion of the main body 1, and is turned on by electricity applied from a rechargeable battery attached to the back of the mobile phone in response to a signal outputted from the signal output unit. The motor 22 thus generates an opposite directional rotating force.
The reduction gear assembly 23 is assembled with an output shaft of the motor 22, and transmits the rotating drive force of the motor 22 to the power transmission unit while lowering the rotating speed at a predetermined ratio. The reduction gear assembly 23 is comprised of a plurality of planetary gears (not shown). In the reduction gear assembly 23, the planetary gears are assembled to have a predetermined reduction ratio, and function to prevent undesired reverse rotation of the reduction gear assembly 23, in addition to lowering the rotating speed.
Therefore, in an automatic operation of the hinge apparatus 10, the rotating drive force of the motor 22 of the power generating unit is transmitted from the output shaft of the motor 22 to the power transmission unit while the rotating speed is lowered by the planetary gears of the reduction gear assembly 23.
The power transmission unit is comprised of a rotary cam 24 and a fixed cam 25. The rotary cam 24 is housed in the housing 21, and is connected to the reduction gear assembly 23 via a shaft. The rotary cam 24 is also tapered at an end thereof such that the central portion of the end of the rotary cam 24 becomes flat and projects toward the fixed cam 25, thus forming a tapered projection.
The fixed cam 25 is received in the second fixed hinge part 31 while being biased toward the rotary cam 24 by the elastic support member 40. The fixed cam 25 has a depression tapered at opposite side surfaces thereof. During an automatic fold rotating mode of the hinge apparatus, the rotary and fixed cams 24 and 25 come into frictional engagement with each other due to the elastic biasing force of the elastic support member.
The elastic support member 40 preferably comprises a compression coil spring made of a material having both high elastic strain and high restoring force. The elastic support member 40 is set in a cavity of the second fixed hinge part 31 such that a first end of the elastic support member 40 is stopped by an end wall of the cavity, and a second end is stopped by an end of the fixed cam 25.
The elastic biasing force of the elastic support member 40 is higher than the rotating drive force of the power generating unit. Since the elastic support member 40 having such a high elastic biasing force biases the power transmission unit in a direction, the rotary and fixed cams 24 and 25 of the power transmission unit may engage with or disengage from each other.
The two fixed hinge parts 30 and 31 are integrally formed at corners of the hinged end of the main body 1. In order to accomplish a hinged connection of one end of the rotary hinge part 20 to the first fixed hinge part 30, a hinge sleeve 32 is inserted into the first fixed hinge part 30. In addition, the fixed cam 25 is inserted into the second fixed hinge part 31 while being biased toward the rotary cam 24 by the elastic support member 40, as described above.
When the fold 2 is assembled with the main body 1 into a single structure by the hinge apparatus, both ends of the rotary hinge part 20 are hinged to the two fixed hinge parts 30 and 31, respectively. That is, the housing 21 of the rotary hinge part 20 is primarily assembled with the hinge sleeve 32 of the first fixed hinge part 30, so that the first end of the rotary hinge part 20 is hinged to the first fixed hinge part 30.
Thereafter, the second end of the rotary hinge part 20 is hinged to the second fixed hinge part 31. In such a case, the fixed cam 25 is primarily inserted into the second fixed hinge part 31 by the use of a fixed cam compressing device (not shown). Due to the fixed cam compressing device, the fixed cam 25 is maintained in the second fixed hinge part 31 while compressing the elastic support member 40. After the fixed cam 25 is inserted into the second fixed hinge part 31 by the use of the fixed cam compressing device, the rotary hinge part 20 is horizontally aligned with the second fixed hinge part 31 such that the second end of the rotary hinge part 20 is fitted over and assembled with the second fixed hinge part 31. Thereafter, the fixed cam compressing device is removed from the fixed cam 25, so that the fixed cam 25 is elastically pushed toward the rotary can 24 by the elastic support member 40 and the rotary and fixed cams 24 and 25 come into frictional engagement with each other. The fold 2 is thus completely assembled with the main body 1 into a single structure by the hinge apparatus.
However, the above-mentioned hinge apparatus is problematic as follows. That is, when the rotary hinge part 20 is horizontally aligned with the second fixed hinge part 31 such that the second end of the rotary hinge part 20 is assembled with the second fixed hinge part 31, the second end of the rotary hinge part 20 scratches the interior surface of the second fixed hinge part 31. The scratches on the second fixed hinge part 31 cause wobble of the rotary cam 24 and the motor of the power generating unit, thus degrading the operational performance of the hinge apparatus due to the wobble.
In addition, it is necessary to compress the fixed cam 25 by the use of a fixed cam compressing device until the second end of the rotary hinge part 20 is horizontally aligned with the second fixed hinge part 31. Therefore, the second end of the rotary hinge part 20 often interferes with the second fixed hinge part 31 during a process of assembling the hinge apparatus, so that it is difficult to assemble the hinge apparatus.
Furthermore, since both the elastic support member 40 and the fixed cam 25 are installed in the second fixed hinge part 31, it is almost impossible to provide mobile phones having a variety of designs which are accomplished by a change in the design of the second fixed hinge part 31. For example, the two fixed hinge parts provided in a hinge apparatus of a mobile phone shown in FIG. 3 have a smoothly rounded appearance to be attractive to users, thereby attracting users' attention. However, the second fixed hinge part 31 of the conventional hinge apparatus must define a large space so as to receive both the elastic support member 40 and the fixed cam 25 therein, so that the second fixed hinge part 31 does not allow mobile phone manufacturers to provide mobile phones having a variety of new designs which are accomplished by a change in the design of the second fixed hinge part 31.
Another disadvantage of the conventional hinge apparatus for mobile phones resides in that the elastic biasing force of the elastic support member 40 is applied to the fixed cam 25 and to the rotary cam 24 engaging with the fixed cam 25, and the transmitted biasing force is, thereafter, applied to the hinge sleeve 32 of the first fixed hinge part 30 through the housing 21 of the rotary hinge part 20, thus enlarging the gap between the rotary hinge part 20 and the first fixed hinge part 30 to wider than a predetermined reference gap.